Download GTU BE/B.Tech 2018 Winter 7th Sem Old 172403 Power Processing Circuits Ii Question Paper

Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2018 Winter 7th Sem Old 172403 Power Processing Circuits Ii Previous Question Paper

1
Seat No.: ________ Enrolment No.___________

GUJARAT TECHNOLOGICAL UNIVERSITY

BE - SEMESTER ?VII (OLD) EXAMINATION ? WINTER 2018
Subject Code: 172403 Date: 26/11/2018

Subject Name: Power Processing Circuits - II

Time: 10:30 AM TO 01:00 PM Total Marks: 70

Instructions:

1. Attempt all questions.

2. Make suitable assumptions wherever necessary.

3. Figures to the right indicate full marks.

Q.1 (a) Explain active front-end rectifier with necessary diagram. List disadvantages of
controlled rectifier and advantages of active front-end rectifier.
07
(b) Explain the working principle of inverter. List and explain its performance
parameters.
07

Q.2 (a) Classify inverters. Explain the operation of a single-phase half bridge inverter
with necessary diagrams and waveforms.
07
(b) Define the following:
Dwell Time, Modulation Index, Cyclo-converter, UPS, THD, MTTR, MTBF.
07
OR
(b) List different types of PWM used for the control of inverters. Explain sine
triangle PWM with neat diagrams.
07

Q.3 (a) Classify multilevel inverters. Explain the basic principle of multilevel inverter
giving its applications.
07
(b) Explain the 120? conduction mode of operation of VSI with circuit diagram and
waveforms.
07
OR
Q.3 (a) Explain five-level diode-clamped single-phase multilevel inverter with circuit
diagram and waveforms.
07
(b) Explain the 180? conduction mode of operation of VSI with circuit diagram and
waveforms.
07

Q.4 (a) Explain Integral Cycle Control method for AC voltage controllers. 07
(b) Explain the input side control techniques of an inverter with necessary diagrams. 07
OR
Q.4 (a) Derive the THD in the output voltage waveform of a square inverter assuming
suitable values. THD is the measure of what for an inverter?
07
(b) Write a note on parallel resonant pulse inverter. 07

Q.5 (a) A 30 KVA UPS is to be employed for RL load with power factor of 0.8. The
backup time required is 30 minutes. Assuming the UPS efficiency to be 85%,
select a suitable Pb-Acid battery (find KW/cell capacity) for the same. Take
minimum allowable battery voltage as 24 Volts and final V/cell=1.75 V.
07
(b) Explain the single-phase to single-phase step-down midpoint cyclo-converter
with discontinuous load current. Draw circuit diagram and waveforms.
07
OR

Q.5 (a) List various methods of battery charging. Discuss any one in brief. 07
(b) Differentiate: On-line and Off-line UPS 07

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